This invention relates to the field of variable-length extension handles, and more particularly to extension handles having the capability of delivering pressurized liquid through a conduit forming a part of the handle.
In the prior art numerous handles are known which allow an operator to apply a liquid to a distant surface. In the earliest manifestation, the only function of the handle was to extend the operator's reach. After each application, the applicator would be returned and re-wet with more liquid.
With the advent of continuous feed applicators, extension handles were adapted to provide a continuous supply of liquid to the applicator, usually by the attachment of a flexible feed hose to the handle, and connecting the hose to deliver liquid to the applicator. Such devices are difficult to maneuver and are susceptible to damage and leakage.
Leakage does not create great difficulties where the liquid is an aqueous cleaning solution for cleaning exterior windows, for example, for the cleaning solution causes nominal harm to the operator and usually is a minor inconvenience.
However, when the liquid is paint or other similar coating material, the potential to cause harm to the operator is increased by the inherent toxicity of the paint. Further, paint spilled about the environment where it is not wanted may cause permanent damage to fixtures such as carpets. Even when no permanent damage is done additional cleanup costs accrue.
Currently it is common to apply liquid at higher pressures, using systems where the delivery pressure approaches 3,000 psi. As pressures are increased the problem of leakage is aggravated since joints and seals have a greater propensity to leak at higher pressures.
A more significant problem is created by the higher pressures making possible leakage to occur in a continuous stream. The high pressure leak can project itself across the environment and impact on a distant surface where leakage is not expected, causing damage to that surface. A serious problem is created by very small pinhole leaks of the liquid from the liquid delivery conduit, such pinhole leaks may eject a stream of liquid so small that the stream cannot be seen by the operator. At these high pressures the liquid stream, rather than simply impacting on the surface of the operator's skin, has sufficient pressure to transgress the skin and inject the liquid inside the operator's body. Virtually all liquids have some toxicity in the human body. The toxicity may be lesser, as when the liquid is nonsterile water, or the liquid may be fatally toxic as with some coating materials inherently having a high level of toxicity.